Abstract: Various exemplary embodiments relate to an energy saving device which supplies high efficiency sodium-vapor street lights and a method of providing additional savings of electrical energy by means of the temporary reduction in the luminous flow of a high efficiency sodium-vapor street light. The energy saving device includes in its operation protection against low voltage supply, regulation of supply voltage, and protection in absence or damage of the lamp. In turn, the method includes a sequence for reliable ignition of the lamp, a modulation routine in frequency for elimination of acoustic resonance, and an automatic turn off sequence in view of damage of the photocell, as well as a consumption detection system to keep the output power steady and therefore, keep the power consumption under a steady value.